Acoustic Wave Microfluidics Using SRBW for High-Rate Atomisation
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Solution Overview
Problem
Current acoustic wave microfluidic devices, such as SAW nebulisation devices, have limited nebulisation or atomisation rates insufficient for effective patient dosing in pulmonary drug delivery, and increasing RF power or liquid supply rates leads to thermal issues and collateral damage.
Innovation Solution
The device utilizes a combination of SAW and surface reflected bulk waves (SRBW) to enhance acoustic wave energy utilization, allowing for efficient microfluidic manipulation, including configurations that satisfy λ SAW /h ~ 1 to maximize acoustic wave energy and achieve nebulisation rates greater than 1 ml/min.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF power level is increased to achieve increased atomisation rates, then atomisation rate is improved, but thermal loading on substrate and components increases
Solution Approach 1:
The patent changes the physical parameters of the device by adjusting substrate thickness to satisfy specific relationships with acoustic wavelength (λ/4, λ/2, 3λ/4, or λ) and modifying the substrate configuration from conventional single-sided SAW to multi-sided SRBW generation. This enables efficient atomisation at lower RF power levels, resolving the contradiction between productivity and temperature.
2Productivity
If RF power level is increased to achieve increased atomisation rates, then atomisation rate is improved, but device size increases due to large power supplies
Solution Approach 1:
By changing the substrate thickness parameter and acoustic wave configuration, the device achieves high atomisation rates at low RF power levels, eliminating the need for large power supplies and reducing overall device size and weight.
3Productivity
If RF power level is increased to achieve increased atomisation rates, then atomisation rate is improved, but collateral damage to drug molecules occurs due to denaturation
Solution Approach 1:
The patent employs parameter changes in substrate thickness and acoustic wave mode to enable efficient energy transfer at low RF power levels, preventing thermal denaturation of drug molecules while achieving clinically required atomisation rates.
4Productivity
If liquid supply rate is increased to achieve increased atomisation rates, then atomisation rate is improved, but device drowning occurs and atomisation stops
Solution Approach 1:
By optimizing substrate thickness and acoustic wave parameters, the device achieves high atomisation efficiency at low liquid supply rates, preventing device drowning while maintaining continuous reliable atomisation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves high and efficient atomisation rates, suitable for pulmonary drug delivery and other applications, with compact size and low cost, incorporating battery power for portability and versatility.
Implementation Method 1
SAW microfluidic devices comprise an interdigital transducer (IDT) on a piezoelectric substrate. Radio frequency (RF) power is applied to the IDT to generate SAW that passes through liquid on the substrate to generate aerosol drops.
Implementation Method 2
SRBW refers to bulk acoustic waves (BAW) propagating along the first and second surfaces by internal reflection through the substrate between the first and second surfaces.
Data Source
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Figure 2
Figure 3~4
AI summary
A device, comprising: an electroacoustic transducer on a substrate; a power supply to supply electromagnetic wave energy to the electroacoustic transducer; and a source of a substance that is movable to the substrate; wherein the electroacoustic transducer and the substrate are configured to generate acoustic wave energy that is used to move the substance from the source to the substrate, and to manipulate the substance on the substrate.